(a) Field of the Invention
The present invention relates to a counter, and more specifically to a counter equipped with a novel zero-resetting device.
(b) Description of the Prior Art
Most of the conventional counters have such a construction as shown in FIG. 1 and FIG. 2. In these figures, the reference numeral 1 represents a frame, and the reference numerals 3, 4 and 5 designate digit wheels which are equipped with heart-shaped cams 3a, 4a and 5a, driven gears 3b, 4b and 5b and further digit-shift pins 3c, 4c and 5c having two teeth. Said digit wheels are supported on a support shaft 2. The reference numeral 6 denotes a pinion mount rotatably mounted by a support shaft 6a on the frame 1 and having reset finger 7 on which a compressing portion is formed to compress said heart-shaped cams. The reference numeral 8 represents a support shaft attached to the pinion mount 6, the reference numerals 9, 10 and 11 designate pinions supported respectively on the shaft 8 and having teeth 9a, 9b; 10a, 10b; and 11a, 11b on the right and left sides respectively as illustrated. On the right sides of the pinions 10 and 11 among these pinions, the teeth 10b and 11b are alternately longer (i.e., longitudinally thicker). The reference numeral 12 denotes an auxiliary gear which is rotatably supported on the support shaft 2, engaged with the pinion 9 and has a worm gear 12a. The reference numeral 13 represents a rotational drive shaft which is supported on the frame 1, and equipped at one end thereof with a worm 13a engaged with the worm gear 12a and at the other end thereof with a pulley 13b. The reference numeral 14 designates a resetting lever. In a counter having such a construction as described above, the pinion mount 6 is always pressed by a spring 15 in the direction opposite to that indicated by an arrow B in FIG. 1, the pinion 9 is engaged with the auxiliary gear 12 and driven gear 3b, the pinion 10 is engaged with the driven gear 4b, the pinion 11 is engaged with the driven gear 5b respectively, and the reset finger 7 is located apart from the heart cams 3a, 4a and 5a. Therefore, when the pulley 13b is rotated with a belt (not shown) passing around said pulley, the rotational drive shaft 13 is rotated, and its rotation is transmitted to the worm 13a, worm gear 12a, auxiliary gear 12, pinion 9 and driven gear 3b, whereby the digit wheel of the units stage is rotated and then the other digit wheels 4 and 5 are rotated in the known sequence to count number of rotations of the rotational drive shaft 13. In order to reset the counter at zero at the subsequent step, the resetting lever 14 is pushed in the direction indicated by the arrow A in FIG. 1. Since this pushing of the resetting lever 14 causes the pinion mount 6 to be rotated around the support shaft 6a in the direction indicated by the arrow B in FIG. 1, the pinions 9, 10 and 11 are disengaged from the auxiliary gear 12, driven gears 3b, 4b and 5b respectively, and the compressing portion of the reset finger 7 compresses simultaneously the heart cams 3a, 4a and 5a which are formed integrally with the digit wheels regardless of positions thereof, whereby said digit wheels are reset at the zero positions. In resetting such a conventional counter at zero, the resetting lever is pushed to rotate the pinion mount 6, which in turn shifts the pinion shaft 8 attached thereto together with the pinions 9, 10 and 11 to disengage these pinions from the driven gears 3b, 4b and 5b arranged on the digit wheels 3, 4 and 5, whereafter the heart cams 3a, 4a and 5a are compressed by the compressing portion formed on the reset finger 7 of the pinion mount. In order to disengage the pinions 9, 10 and 11 from the driven gears 3b, 4b and 5b formed on the digit wheels 3, 4 and 5, it is required to shift each of the pinions, thereby making it necessary to reserve space for this purpose which constitutes hindrance in designing a compact counter. In addition, the conventional counter has another defect to require a large number of component members including, for example, a restricting spring 16 on the pinion mount in order to prevent the pinions from being rotated in disengaging the pinions from the driven gears.